1. Install Kobalt

With HomeBrew

If you are on MacOS and have brew installed:

$ brew install kobalt
$ which kobaltw
/usr/local/bin/kobaltw

Manually

Download the zip file, unzip it and add the bin directory to your $PATH variable so that you can invoke the command kobaltw:

cd yourLocation
unzip kobalt-xxx.zip
cd kobalt-xxx
export PATH=$PWD/bin:$PATH

2. Initialize your project

Change to your project directory and call the kobaltw command with --init:

cd ~/java/project
kobaltw --init java

cd ~/java/project
kobaltw --init kotlin

to initialize a Kotlin project.

This command will do two things:

1. Create a default kobalt/src/Build.kt file based on what was found in your project.
2. Install the Kobalt Wrapper in your current directory (a script called kobaltw) and a few additional files in the kobalt/wrapper directory.

From now on, you can just use ./kobaltw to build and you can ignore the kobaltw on your path, which is only useful to install Kobalt on new projects. Since you will now build each project with its own ./kobaltw command, they will use their own version of Kobalt.

3. Edit kobalt/src/Build.kt

If your project uses a standard folder structure, you can skip this section and try to build your project directly.

The build file generated by default might need some editing before you can build your project, so take a look at it and adjust whatever is necessary (e.g. package name, version, etc...)

Here is the Build.kt for the JCommander project:

import com.beust.kobalt.*
import com.beust.kobalt.plugin.java.*
import com.beust.kobalt.plugin.packaging.*
import com.beust.kobalt.plugin.publish.*

val jcommander = project {
    name = "jcommander"
    group = "com.beust"
    artifactId = name
    version = "1.54"

    dependenciesTest {
        compile("org.testng:testng:6.9.9")
    }

    assemble {
        mavenJars {
        }
    }

    jcenter {
        publish = true
    }
}

4. Build your project

You can now attempt to build your project with Kobalt:

./kobaltw assemble

5. IDEA users: generate IDEA files

If you are planning to use IDEA to work on your project, you can ask Kobalt to generate all the IDEA files necessary to import your project:

./kobaltw --init idea

This will generate several files depending on the content of your build file. You can then launch IDEA and open this project directly.

6. IDEA users: sync your build file

If you're using Intellij IDEA, make sure you've installed the Kobalt plugin and then go to Kobalt -> Sync Build File. Once the build file is synchronized, the errors should disappear and you can now use all the regular functions of IDEA on Build.kt just like any other Kotlin files (auto completion, jump to symbol, etc...).

7. Next steps

From this point, you can either learn how to install the Kobalt IDEA plug-in or read Kobalt's documentation.